This invention relates to a replaceable cutter tooth having three outwardly diverging cutting tips. The invention is particularly adapted use in combination with a tooth holder assembly mounted to the outer peripheral surface of a rotatable cutter drum used for clearing, mulching, and grinding trees. The cutter drum is movably mounted on the boom of a backhoe. During operation of the cutter drum, the teeth become worn or damaged and must be periodically replaced. A complete description of Applicant's cutter drum is provided in U.S. Pat. Nos. 5,692,689 and 5,794,866. This description is incorporated herein by reference.
One problem in the art which is addressed by a third patent issued to the present applicant, U.S. Pat. No. 5,873,534, relates to damage and wear of cutter teeth over a relatively short period of use, and the overall performance of the cutter teeth in terms of cutting and mulching trees. This patent describes a four-tipped cutter tooth which mounts to the outer surface of the cutter drum such that three of the four tips reside in a cutting or mulching position spaced apart from the drum surface, while one of the cutting tips fits within a groove formed in a tooth holder assembly used to secure to the tooth to the drum. When the cutting tip in the outermost cutting position becomes worm, the cutter tooth is rotated 180 degrees so that the fresh tip once positioned in the groove is now located in the cutting position. This combination cutter tooth and tooth holder assembly overcame many drawbacks and limitations in the prior art relating to the replacement, useful life, and performance of cutter teeth.
The present invention further improves this combination by providing a three-tipped cutter tooth and tooth holder assembly which mounts to the outer surface of the cutter drum. During operation of the cutter drum, two of the three cutting tips reside in a reduced wear position adjacent the tooth holder assembly, while only a single tooth resides in an increased wear position for cutting and mulching. When the cutting tip in the cutting position becomes worn, the cutter tooth is rotated so that one of the two fresh tips takes its place. According to this design, less energy is required to operate the drum, since less surface area of the tooth actually engages and penetrates the tree during cutting. Moreover, the reduced surface area of the tooth in the cutting position results in less drag force acting against rotation of the drum.